Manufacturing method of electronic component, manufacturing apparatus thereof, and driving method of manufacturing apparatus thereof

ABSTRACT

In manufacturing an electronic component composed of a plastic molded part having a built-in electronic element, and leads projecting from the plastic molded part, a first partial lead section, between an intermediate section and a tip section, of each lead of the electronic component is bent downward. The first section of each lead is bent from the side toward a bottom of the plastic molded part after further bending a base of each lead.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a manufacturing method of an electronic component that has a plastic molded part having a built-in electronic element, and leads projecting from the plastic molded part, a manufacturing apparatus thereof, and a driving method of the manufacturing apparatus, and in particular, to the bending of leads of an electronic component.

[0003] 2. Description of the Related Art

[0004]FIGS. 9A and 9B are a perspective view of a quartz resonator and an explanatory diagram of its leads, respectively. This quartz resonator 1 is composed of a plastic molded part 2 having a built-in electronic element or the like, and leads 3 projecting from the plastic molded part 2. In addition, a concavity 2 a to contain each end section of the leads 3 is provided in a bottom of the plastic molded part 2. The leads 3 are bent toward the bottom of the plastic molded part 2 thus surrounding each side of the plastic molded part 2. Each end section of the leads 3 is contained in the concavity 2 a. It is necessary that each base of the leads 3 is bent inside so that a bending angle a becomes nearly 0-10°. In this manner, thinning and miniaturization are achieved by reducing the height of the quartz resonator 1 including the plastic molded part 2 and leads 3. However, since each of the leads 3 has such a shape as described above, a bending method of merely lowering a punch from above, that is, push bending cannot form such a shape because the leads 3 spring back.

[0005]FIG. 10 is an explanatory diagram of a cam mechanism to bend the leads of a quartz resonator as described above. This cam mechanism is a mechanism for the final stage of bending the leads (this corresponds to a fourth bending in FIG. 6 described later). This cam mechanism consists of cam drivers 11 provided on a punch plate side, and cam levers 12 rotatively supported and provided on a die plate side. An end of the cam driver 11 engages with a cam lever 12 when the cam driver 11 is lowered, and the cam lever 12 rotates inwardly to bend leads 3 to the inside.

[0006] When electronic components are mass-produced in the traditional cam mechanism as the above, there are the following problems.

[0007] (1) Part shapes are complicated, and hence maintenance is difficult. Shapes of the cam lever 12 and a lever holder 13 are complicated. In particular, it is frequently necessary to perform fine adjustment at the time of part replacement because it is difficult to make a shape of the cam lever 12 correspond exactly to a pinhole 14.

[0008] (2) Cam lever shafts 15 are thin (due to constraints on the mechanism), and weak. In addition, since the shaft 15 is free and a rotational range of the cam lever 12 is narrow and fixed, the shaft 15 tends to wear out. If the cam lever shaft 15 wears, a bending failure arises because the location of the cam lever 12 is shifts.

[0009] (3) Since the cam mechanism (cam lever) is provided in a lower mold die set, punched chips of a plastic mold (package) easily get into the mechanism and interfere with its operation so that the punched chips affect the precision of bending.

[0010] For example, the cam mechanism may get stuck at the position of the cam lever 12 shown on the right side in FIG. 10 and prevented from rotating because punched chips do not fall beneath it. Also, if a large punched chip exists in part “A” in FIG. 10, the cam lever 12 cannot rotate to a last position, and hence each of the leads 3 is not bent to a predetermined position. Since the plastic mold package is transferred to a next stage without being properly processed, problems arise such as parts being destroyed or a mold being damaged.

Summary of the Invention

[0011] An object of the present invention is to solve the above problems. A particular object of the present invention is to provide a method of manufacturing an electronic component, wherein maintenance is easy and high precision bending is achieved, and to provide a manufacturing apparatus therefor, and a driving method for the manufacturing apparatus.

[0012] According to an aspect of the present invention, a method is provided for manufacturing an electronic component that includes a plastic molded part having a built-in electronic element, and leads projecting from the plastic molded part. This manufacturing method includes at least a first step of forming a first bent section by bending a first section of each lead, a second step of bending each lead near its base, and a third step of further bending the bent section near the base of each lead by horizontally pressing, for example, a section between the neighborhood of the base and the first bent section in each lead. Since each lead is horizontally pressed in the third step, damage, such as scratches, are minimized on a surface of each lead, and an end of each lead is bent with high accuracy toward the bottom of the electronic component.

[0013] According to another aspect of the present invention, the first bent section is formed between a tip section and a middle section of each lead. By horizontally pressing the section between the base and the first bent section when further bending the bent section near the base, a large bending stress is achieved in the neighborhood of the base, so that bending work is performed with high accuracy.

[0014] According to still another aspect of the present invention, the first bent section is bent in a plurality of bending sub-steps. Thus, the amount of bending per bending operation is small so that the occurrence of lead spring-back is reduced.

[0015] According to a further aspect of the present invention, the electronic component is a quartz resonator such that a thin quartz resonator can be realized with the present invention.

[0016] According to a still further aspect of the present invention, an apparatus for manufacturing an electronic component by bending each lead formed in the electronic component, includes upper and lower molds. A cam that moves horizontally to bend leads is included in the lower mold. In addition, a cam driver is included in the upper mold, and the cam is moved horizontally by driving the cam driver. As a result, there is less damage, such as scratches on a surface of each lead, thereby resulting in higher quality products. Furthermore, highly precise bending is possible because the quantity of spring-back is small. In addition, this cam mechanism does not require a lever shaft like a conventional cam lever mechanism, and therefore does not have parts that wear out quickly, thus reducing maintenance time and complications.

[0017] According to another aspect of the present invention, a spring or other resilient member separates the cam from a bending die to form a gap therebetween. As a result, the cam is usually away from the bending die and punched chips of packages can easily pass between the components.

[0018] According to still another aspect of the present invention, the cam slides in a horizontal direction by a flat roller. Thus, even if punched chips of packages or the like adhere, sliding can still be achieved.

[0019] According to a further aspect of the present invention an apparatus is provided for manufacturing an electronic component that has a plastic molded part having a built-in electronic element, and leads projecting from the plastic molded part. This manufacturing apparatus includes at least a first bending punch for forming a first bent section by bending a first section of each lead, a first bending die formed corresponding to the first bending punch, a second bending punch for bending each lead near its base, a second bending die arranged corresponding to the second bending punch, and a cam driver that drives a third bending punch in a horizontal direction to further bend each lead near its base. Since a drive amount of the bending punch depends on a relative horizontal position between the cam driver and bending punch, regulation of a constant drive amount can be easily realized. Furthermore, highly precise bending becomes possible because the spring-back is limited. In addition, this cam mechanism does not require a lever shaft like a conventional cam lever mechanism, and therefore does not have parts that wear out quickly, thus reducing maintenance time and complications.

[0020] According to a still further aspect of the present invention the manufacturing apparatus further includes a fourth bending punch for further bending the first bent section, and a third bending die arranged corresponding to the fourth bending punch in the item. Thus, the amount of bending per bending operation is small, so that the occurrence of spring-back of leads caused by bending is reduced.

[0021] According to another aspect of the present invention, each end section of the first, second, and fourth bending punches is formed in a curved face shape. Since an end section of each bending punch is formed in the curved face shape, leads are not scratched at the time of being pressed down.

[0022] According to still another aspect of the present invention, through-holes are formed around the bending dies to allow passage of punched chips of leads. Thus, the punched chips of plastic mold packages and leads are disposed through the through-holes.

[0023] According to a further aspect of the present invention, at least a part of the first bending die approaches each lead near its base during bending. Thus, the bending of leads is stably performed.

[0024] According to a still further aspect of the present invention, each bending punch, each bending die, and the cam driver are formed so as to bend leads formed along a longitudinal axis (or major axis) of the electronic component. The present invention can be thus be applied to the electronic component whose leads are formed along a longitudinal or major axis.

[0025] According to another aspect of the present invention, each bending punch, each bending die, and the cam driver are formed so as to bend leads formed along a latitudinal axis (or minor axis) of the electronic component. As a result, the present invention can be applied to the electronic component whose leads are formed along a latitudinal or minor axis.

[0026] According to an aspect of the present invention, there is provided a driving method for a manufacturing apparatus of an electronic component that has a plastic molded part having a built-in electronic element, and leads projecting from the plastic molded part. This driving method includes the steps of driving a first bending punch to bend a first section of each lead, driving a second bending punch to bend each lead near its base, and driving a cam driver to further bend each lead near its base. As a result, there is less damage, such as scratches on a surface of each lead, thereby resulting in higher quality products. Furthermore, highly precise bending is possible because the quantity of spring-back is small. In addition, this cam mechanism does not require a lever shaft like a conventional cam lever mechanism, and therefore does not have parts that wear out quickly, thus reducing maintenance time and complications.

[0027] According to another aspect of the present invention, in the foregoing driving method the step of driving the cam driver comprises driving a third bending punch horizontally with the cam driver. As a result, an end of each lead is bent with high accuracy toward a bottom of the electronic component with minimal damage, such as scratches, on the surface of the leads.

[0028] Other objects and attainments together with a fuller understanding of the invention will become apparent and appreciated by referring to the following description and claims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In the drawings wherein like reference symbols refer to like parts

[0030]FIG. 1 is a detailed view of a periphery of a cam driver and bending punches in a mold machine of the present invention shown in FIG. 2;

[0031]FIG. 2 is a cross sectional view showing the configuration of the mold machine in which a manufacturing apparatus of electronic component according to an embodiment of the present invention is built in;

[0032]FIG. 3 is an explanatory diagram of a first bending operation by bending punches and a bending die of the present invention;

[0033]FIG. 4 is an explanatory diagram of a second bending operation by bending punches and a bending die of the present invention;

[0034]FIG. 5 is an explanatory diagram of a third bending operation by bending punches and a bending die of the present invention;

[0035]FIG. 6 is an explanatory diagram of a fourth bending operation by bending punches of the present invention;

[0036]FIG. 7 is a diagram illustrating the motion of each part in FIG. 1 at the time of performing the fourth bending operation shown in FIG. 6;

[0037]FIG. 8 is a perspective view of a first electronic component such as a quartz resonator;

[0038]FIGS. 9A and 9B are a perspective view of a second electronic component such as a quartz resonator and an explanatory diagram of its leads, respectively; and

[0039]FIG. 10 is an explanatory diagram of a cam mechanism to bend the leads of the electronic component such as a quartz resonator shown in FIGS. 9A and 9B.

DETAILED DESCRIPTION

[0040]FIG. 2 is a cross sectional view showing the construction of a mold machine in which an apparatus for manufacturing an electronic component (for example, a quartz resonator, or other integrated circuit device) according to an embodiment of the present invention is built in. In this mold machine, as shown in FIG. 2, an upper mold backing plate 101 is installed on a lower side of an upper mold die set 100, and further, a punch plate 102 is installed on a lower side of the upper backing plate 101. A stripper plate 103 elastically supported by the upper mold die set 100 is arranged underneath this punch plate 102, and, stripper pieces 104-106 are installed on a lower side of this stripper plate 103.

[0041] In the punch plate 102, a resin cut punch A 110, a resin cut punch B 111, a tie bar cut punch 112, a lead cut punch 113, a bending punch A 114, a bending punch B 115, a bending punch C 116, a cam driver 117, and a pinch cut punch 118 are installed along from the upstream of work to the downstream. Then, these pass through holes provided in the stripper plate 103 and stripper pieces 104-106 and project underneath in accordance with the lowering of the upper mold die set 100. In addition, an upper stopper 120 and a misfeed pin 121 are installed in the upper mold die set 100 respectively.

[0042] With facing the upper mold die set 100, the lower mold die set 200 is arranged thereunder. On its upper surface, a lower mold backing plate 201 is installed, and a die plate 202 is further installed thereon. In this die plate 202, a resin cut die 210, a tie-bar cut die 212, a lead cut die 213, a bending die A 214, a bending die B 215, a bending die C 216, a bending punch D 217 functioning as a cam, and a pinch cut die 218 are installed along from the upstream of work to the downstream. In addition, a lower stopper 220 is provided in the lower mold die set 200 facing the upper stopper 120. In addition, a hole 221 where the misfeed pin 121 is inserted at the time of pressing is provided in the lower mold backing plate 201 and die plate 202.

[0043]FIG. 1 is a detailed drawing of a periphery of the cam driver 117 and bending punch D 217 in the mold machine shown in FIG. 2. The cam driver 117 is fixed to the punch plate 102 by a fixing key 122. In addition, at a tip section of the cam driver 117, a sloped surface 117 a for engaging the bending punch D 217 is formed. A pair of bending punches D 217 sandwich a lifter pin 230 and a bending die D 231. An end part of a bolt 232 that passes through part of the die plate 202 in a horizontal direction is screwed into each bending punch D 217. Washers 233 and 234 are provided in a head section of the bolt 232 outside the die plate 202, and a spring or other resilient member 235 is positioned therebetween. Hence, the bending punch D 217 is usually forced in such a direction that the bending punch D 217 separates from the bending die D 231. Because a gap is formed between the bending die D 231 and bending punch D 217, the punched chips of a plastic package are easily disposed. In addition, a sloping surface 217 a for engaging with the sloping surface 117 a in an end part of the cam driver 117 is provided in the bending punch D 217. Furthermore, a hole 202 a for permitting the lowering of the cam driver 117 is provided in the die plate 202.

[0044] In addition, a flat roller 236 is provided in a lower part of the bending punch D 217 that allows the bending punch-D 217 to move smoothly in a horizontal direction. Furthermore, a hole 240 is provided at a position corresponding to an outer periphery of the bending die D 231 in the lower mold backing plate 201. Moreover, a hole 241 is also provided at a position corresponding to the hole 240 in the lower mold die set 200, and holes 240 and 241 form a through-hole. In addition, a spring 242 to force a lifter pin 230 upward is arranged in the lower mold die set 200.

[0045] The outline of the operation of the mold machine in FIGS. 1 and 2 is described as follows.

[0046] When the upper mold die set 100 is lowered while being guided by a guidepost (not shown), first, the stripper plate 106 presses a lead frame arranged on the die plate 202 and a plastic molded part mounted on the lead frame. Then, the punch plate 102 is lowered, and the following press working is performed:

[0047] (1) Unnecessary parts of the plastic molded part on the lead frame are cut by the press working performed by the resin cut punch A 110, resin cut punch B 111, and resin cut die 210.

[0048] (2) Tie-bars on the lead frame are cut by the press working performed by the tie-bar cut punch 112 and tie-bar cut die 212.

[0049] (3) Each lead projecting from the plastic molded part is cut to a predetermined length by the press working performed by the lead cut punch 113 and lead cut die 213.

[0050] (4) A first bending work is performed for each lead by press working performed by the bending punch A 114 and bending die A 214 (as shown in FIG. 3).

[0051] (5) A second bending work is performed for each lead by the press working performed by the bending punch B 115 and bending die B 215 (as shown in FIG. 4).

[0052] (6) A third bending work is performed for each lead by the press working performed by the bending punch C 116 and bending die C 216 (as shown in FIG. 5).

[0053] (7) A fourth bending work is performed for each lead by the press working performed by the bending punch D 217 through driving the bending punch D 217 by the cam driver 117 (as shown in FIG. 6).

[0054] (8) The plastic molded part, in which each lead has been bent, is separated by pressing an upper surface of the plastic molded part in the press working performed by the pinch cut punch 118 and pinch cut die 218. The electronic component is ejected underneath through the hole 201 a provided in the lower mold backing plate 201 and the hole 200 a provided in the lower mold die set 200.

[0055] The press working in the above items (1) to (8) can be performed simultaneously. However, the press working in the above items (1) to (8) is performed in sequence for a quartz resonator on a lead frame because the lead frame is transferred from upstream to downstream in turn in each press working operation. In addition, the misfeed pin 121 is used to detect a feed amount of a lead frame. If the feed amount of a lead frame is suitable, the misfeed pin 121 arrives at the hole 221 through each hole provided in the lead frame in predetermined intervals. However, if the feed amount of a lead frame is not suitable, the misfeed pin 121 collides with the lead frame. The press working is stopped by stopping the lowering the upper mold die set 100 in such case by detecting a moving amount of the misfeed pin 121. In addition, the upper stopper 120 and lower stopper 220 oppositely arranged perform appropriate press working by regulating a lowering amount of the upper mold die set 100, that is, each punch.

[0056]FIG. 3 is an explanatory diagram of the first bending work by the bending punch A 114 and bending die A 214. The first bending work is performed by bending each partial lead 3 a between an intermediate part and a tip part of each lead 3 downward (for example, a bent angle of the lead 3 is 135°) through the press working by the bending punch A 114 and bending die A 214 for the leads 3 projecting from both sides of the plastic molded part.

[0057]FIG. 4 is an explanatory diagram of the second bending work by the bending punch B 115 and bending die B 215. The second bending work is performed by further bending each partial lead 3 a (for example, a bent angle of the lead 3 is 87°) through the press working by the bending punch B 115 and bending die B 215, for the lead 3 where the first bending work shown in FIG. 3 has been performed. Incidentally, the bending work is performed for the same location (the location between the tip part and intermediate part of the lead 3) in the first bending work and second bending work. By performing the bending work in a plurality of bending sub-steps, i.e. dividing the bending work of the same location into multiple, separate bends in this manner, a bending amount per bending operation is reduced so that spring-back of the leads does not occur.

[0058]FIG. 5 is an explanatory diagram of the third bending work by the bending punch C 116 and bending die C 216. The third bending work is performed by bending each base part near the base of the lead 3 (for example, a bent angle of the base part of the lead 3 is 110°) through the press working by the bending punch C 116 and bending die C 216 for the lead 3 where the second bending work shown in FIG. 4 has been performed.

[0059] In addition, each end section of the bending punch A 114, bending punch B 115, and bending punch C 116 is formed with a curved face shape. Thus, leads 3 are not scratched at the time of the press working. Furthermore, because the bending die A 214 and bending die B 215 are configured to contact each lead near its base, the bending work of the lead 3 can be performed stably.

[0060]FIG. 6 is an explanatory diagram of the fourth bending work by the bending punch D 217. The fourth bending work is performed by further bending the base part of each lead 3 (for example, a bent angle of the base part of the lead 3 is 83° to 87°) through the press working by the bending punch D 217 for a partial lead 3 b between the base and intermediate part in each lead 3 where the third bending work shown in FIG. 5 has been performed. In addition, the slope 217 b is provided on an inner wall side of an end part of the bending punch-D 217 in order to bend the partial lead 3 b at 90° or less.

[0061]FIG. 7 is a diagram for explaining the motion of each part in FIG. 1 at the time of performing the fourth bending work shown in FIG. 6. The bending punch D 217 is usually forced by a spring 235 in a direction such that the bending punch-D 217 is separated from the bending die D 231. However, when the cam driver 117 is lowered and the slope 117 a of its end part is inserted into the hole 202 a of the die plate 202 with engaging with the slope 217 a of the bending punch D 217, that is, the cam driver 117 arrives at a position (3) through positions (1) and (2) in FIG. 7, the bending punch D 217 also moves toward the bending die D 231 and arrives at the position (3) through positions (1) and (2) in FIG. 7, so that the slope 217 b of the bending punch-D 217 presses a partial lead 3 a in a horizontal direction to further bend each lead 3 near its base.

[0062] The following advantages follow from the actions described above with reference to the fourth bending work:

[0063] (1) Since the bending punch D 217 presses the partial lead 3 b horizontally (from its side), there is minimal damage, such as scratches on a face of each lead 3, which results in a superior product.

[0064] (2) In addition, the driving of the bending punch D 217 is limited to a position where the bending punch D 217 disengages from the slope 117 a of the cam driver 117 and a drive amount of the bending punch-D 217 depends on a relative position between the cam driver 117 and bending punch-D 217. Since their relative position is easily controlled with high accuracy, the drive amount can be easily kept constant so that the bending work with high accuracy becomes possible.

[0065] (3) In addition, this cam mechanism does not require a lever shaft like a conventional cam lever mechanism, and therefore does not have parts that wear out quickly, thus reducing maintenance time and complications.

[0066] (4) Although the bending punch-D 217 is provided in the die plate 202, at first, the sliding property of the bending punch-D 217 is secured by a flat roller 236 provided under the bending punch-D 217, as a measure against interference by punched chips of the plastic mold (package). In addition, holes 240 and 241 provided in the lower mold die set 200 and lower mold backing plate 201 form a through-hole, and permit disposal of punched chips to prevent a build-up of punched chips in the mold. Furthermore, in the present invention, although being not shown, through-holes similar to this through-hole are also provided in the resin cut die 210, tie-bar cut die 212, lead cut die 213, bending die-A 214, bending die-B 215, bending die-C 216, and pinch cut die 218 respectively.

[0067] (5) In addition, by pressing down each partial lead 3 b between a base and an intermediate part, the base part of each lead 3 is further bent. Accordingly the appropriate bending can be performed because large pressing-down stress is added to the base part.

[0068] In the above-described embodiment, an example where each bending punch, each bending die, and the cam driver are formed so as to bend leads formed along a minor axis of the electronic component as shown in FIG. 9 is described. However, the present invention can be also applied to the bending of leads 3 formed along a major axis of the electronic component 1 as shown in FIG. 8. In that case, each bending punch, each bending die, and the cam driver are formed so as to correspond to the bending of the leads 3.

[0069] While the invention has been described in conjunction with several specific embodiments, it is evident to those skilled in the art that many further alternatives, modifications and variations will be apparent in light of the foregoing description. Thus, the invention described herein is intended to embrace all such alternatives, modifications, applications and variations as may fall within the spirit and scope of the appended claims. 

What is claimed is:
 1. A method for manufacturing an electronic component that includes a plastic molded part containing a built-in electronic element, and leads projecting from the plastic molded part, comprising: bending a first section of each lead to form a first bent section in each lead; bending each lead near its base; and further bending each lead near its base by horizontally pressing each lead from a side of the molded part.
 2. The manufacturing method according to claim 1 , wherein the step of bending the first section comprises forming the first bent section in each lead between a tip section and a middle section of each lead.
 3. The manufacturing method according to claim 1 , wherein the step of bending the first section comprises a plurality of bending sub-steps.
 4. The manufacturing method according to claim 1 , wherein the electronic component comprises a quartz resonator.
 5. An apparatus for manufacturing an electronic component having leads, comprising: an upper mold and a lower mold; the upper mold comprising a cam driver; and the lower mold comprising a cam that is moved horizontally by the cam driver to bend each lead.
 6. The apparatus according to claim 5 , further comprising a bending die and a resilient member that separates the cam from the die to form a gap therebetween.
 7. The apparatus according to claim 5 , further comprising a flat roller on which the cam slides in a horizontal direction.
 8. An apparatus for manufacturing an electronic component that includes a plastic molded part containing a built-in electronic element, and leads projecting from the plastic molded part, comprising: a first bending punch that bends a first section of each lead to form a first bent section, and a first bending die corresponding to the first bending punch; a second bending punch that bends each lead near its base, and a second bending die corresponding to the second bending punch; a third bending punch; and a cam driver that drives the third bending punch in a horizontal direction to further bend each lead near its base .
 9. The apparatus according to claim 8 , further comprising: a fourth bending punch that further bends the first bent section; and a third bending die corresponding to the fourth bending punch.
 10. The apparatus according to claim 9 , wherein each end section of the first, second, and fourth bending punches each comprise an end section including a curved face.
 11. The apparatus according to claim 8 , further comprising through-holes formed around each of the first, second, and third bending dies to pass punched chips of the leads.
 12. The apparatus according to claim 8 , wherein at least a part of the first bending die approaches each lead near its base during bending.
 13. The apparatus according to claim 8 , wherein each of the first, second, and third bending punches, each of the first and second bending dies, and the cam driver are formed so as to bend leads formed along a major axis of the electronic component.
 14. The apparatus according to claim 8 , wherein each of the first, second, and third bending punches, each of the first and second bending dies, and the cam driver are formed so as to bend leads formed along a minor axis of the electronic component.
 15. A method for driving apparatus for manufacturing an electronic component that includes a plastic molded part containing a built-in electronic element, and leads projecting from the plastic molded part, comprising: driving a first bending punch to bend a first section of each lead; driving a second bending punch to bend each lead near its base; and driving a cam driver to further bend each lead near its base.
 16. The driving method according to claim 15 , wherein the step of driving a cam driver comprises driving a third bending punch horizontally with the cam driver. 